Machine learning and symbolic reasoning have been two main approaches to build intelligent systems. Symbolic reasoning has been used in many applications by making use of expressive symbolic representations to encode prior knowledge, conduct complex reasoning and provide explanations. Recently, machine learning has enabled various successful applications by learning from...
Raytracing is a long-established means to simulate physically accurate light propagation. Increasing availability and power of highly-parallel computing, such as cloud-based clusters and dedicated graphics hardware, means that rendering algorithms can produce high resolution output very quickly. This means raytracing can now be used as a forward model in optimization...
This work presents a cognitive model of argument structure construction acquisition and application based on analogy. The claims of this model are that (1) constructions, pairings of form and meaning, are a productive unit of linguistic analysis that account for a broader range of phenomena than traditional approaches; (2) human...
Modern cosmological simulations are some of the world's largest and most demanding numerical computations that are run on state-of-the-art supercomputers. The codes use N-body and mesh-based methods in gravity-only solvers, and both Lagrangian and Eulerian schemes to model gas dynamics. Even complex astrophysical effects such as of star formation and...
Social media such as Twitter has risen as a powerful new communication medium for disseminating information on news, personal interests, experiences, and opinions. On social media, people talk about their lifestyle, health conditions and symptoms, search information on treatment options, and connect with people who have been through similar medical...
Understanding electrical circuits can be difficult for novices of all ages (Grotzer & Sudbury, 2000; Osborne, 1983; Shipstone, 1984; Tarciso Borges, 1999). Research shows that novices tend to have inadequate understandings of what happens at the level of atoms and electrons, leading to difficulty predicting the outcomes of electrical circuits...
Online platforms for learning to code such as Coursera, CodeCademy, and CodeSchool attract millions of learners and significantly expand the pool of self-starting developers, yet critical gaps in knowledge and experience remain between inexperienced learners and professionals. With vast amounts of professionally-authored source code made readily available by the client-server...
Smartphone is becoming ubiquitous and its sales proportions have exceeded the sales of personal computer systems since 2012. The number of smartphones will increase and perhaps at an even higher rate in the coming years. The computational capacity and numerous mobile applications benefit end user's daily life. At the same...
Serious games that are designed for educational purposes promote acquisition of knowledge and skills that are valued in the both the virtual realm and the real world. The challenge is to design serious games that leverage meaningful play to produce positive learning outcomes in the real world. I argue that...
Embedded systems are ubiquitous. Although many aspects of embedded system design and synthesis have received significant research attention, comparatively less attention has been given to new ideas in memory hierarchy design. This dissertation presents several new operating system and architecture techniques that use elements of the virtual and physical memory...
Technology users are technology observers as well, monitoring for problems or opportunities that might arise. Designing interfaces to support the monitoring of technology presents unique challenges for everything from detecting situations to responding to situations to changing the tools to match a changing operating environment or the observer's changing knowledge....
The light field is a 4D function that describes the flow of light in all directions through every point in free space. Digital cameras only capture a 2D projection of the 4D light field entering the camera lens. In this dissertation I modify the light field as it enters a...
The recent years have witnessed a large number of emerging applications in location based services, thanks to the wide spread use of GPS devices, cellular phones, RFID tags and mobile sensor nodes. A fundamental technology that enables such services is the efficient management of the vast volume of spatio-temporal information...
Virtual machine based distributed computing greatly simplifies and enhances adaptive/autonomic computing by lowering the level of abstraction, benefiting both resource providers and users. We are developing Virtuoso, a middleware system for virtual machine shared-resource computing (e.g. grids) that provides numerous advantages and overcomes many obstacles a user faces in using...
Live streaming media will form a significant fraction of Internet traffic in the near future. YouTube clips, animations and other video applications already account for more than sixty percent of Internet traffic and, at its current acceptance rate, streaming media could quickly surpass television in terms of the size of...
High-performance scientific computing in a modern age uses parallel techniques at a scale of hundreds of thousands of processors. These large-scale applications have I/O system workloads that are primarily driven by small, sparse I/O operations. While parallel file systems have provided application developers with scalable peak I/O bandwidth for large,...
We can represent many real-world data sets as data streams and/or high-dimensional data. Major stock market such as New York Stock Exchange (NYSE) trades more than 8000 financial products daily, which generates massive trading time series in the form of data streams. NetFlow and DNS querying data generated by real-time...
Humans routinely answer questions, make decisions, and provide explanations in the face of incomplete knowledge and time constraints. From everyday questions like "What will it cost to take that vacation?" to policy questions like "How can a carbon taxing scheme affect climate change?" we often do not have all the...
Living in a world where the machine and the Internet are ubiquitous, many people work and play online, in a world that is, ironically, often isolated and lonesome. While the Internet, as intended, connects us to information, products and services, it often draws us away from the rich connections that...
Constructing 3D objects from 2D images has been an active research area for decades. Given captured 2D information from various devices, different techniques were developed to assign 3D positions to the target object. However, methods for reconstructing a 3D model from a single 2D image remain largely manual and labor-intensive....